Wafer separation and detection method

Abstract

To provide a wafer separation detection method, capable of detecting an unseparated region of an adhesive film.SOLUTION: A wafer separation detection method includes: an adhering step 101 of adhering an expanded sheet onto a rear surface of a wafer via an adhesive film; an expanding step 102 of, after the adhering step 101, expanding the expanded sheet; a light application step 103 of, after the expanding step 102, applying light of a wavelength that is absorbable by the adhesive film from one surface side of the wafer 1; and a separation detecting step 104 of, after the light application step 103, detecting whether the light is leaked from a scheduled dividing line on the other surface side of the wafer, and, when the light is leaked, determining that the wafer and the adhesive film are separated, while when the light is not leaked, determining that an unseparated region exists.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for detecting separation of a wafer, which detects whether a wafer divided along a plurality of division planned lines formed in a lattice pattern on the surface is separated along the division planned lines together with an adhesive film attached to the back surface of the wafer.

Background Art

[0002] When dividing a plate-shaped workpiece such as a wafer into a plurality of device chips, for example, a method is used in which a laser beam having a wavelength that passes through the wafer is condensed on a division planned line to form a modified layer along the division planned line on the wafer (see, for example, Patent Document 1). Then, by applying a force to the wafer from the outside, it is divided into a plurality of device chips with the region corresponding to the modified and brittle division planned line as a boundary.

[0003] When stacking and fixing the above-described device chips to another device chip or a substrate, an adhesive film called a die attach film (adhesive film) may be provided on the back surface of each device chip. For example, an adhesive film formed to a size that can cover the entire wafer is attached to the back surface of the wafer before it is divided into device chips, and by dividing this together with the wafer, a plurality of device chips having an adhesive film on the back surface are completed.

[0004] By the way, if a region where the wafer is not completely separated along all the division planned lines remains during division, when picking up individual chips in the subsequent bonding process, an unreasonable force is applied to the non-separated device chips, resulting in damage to the device chips or interference with the bonding operation.

[0005] Therefore, detection methods are used to detect the presence or absence of unseparated regions in wafers after they have been divided, such as irradiating one side of the wafer with light and determining whether or not light is leaking from the planned division line on the other side (see, for example, Patent Document 2). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2002-192370 [Patent Document 2] Japanese Patent Publication No. 2005-251986 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, adhesive films come in various types, differing in material and thickness, and some transmit a large amount of the irradiated light. Even if the device chip is divided, if the adhesive film on its back remains undivided, the detection method described above makes it difficult to detect the unseparated areas of the adhesive film.

[0008] The object of the present invention is to provide a wafer separation detection method that can detect unseparated regions of an adhesive film. [Means for solving the problem]

[0009] To solve the above-mentioned problems and achieve the objective, the wafer separation detection method of the present invention is a wafer separation detection method for detecting whether a wafer having a plurality of division lines formed in a grid pattern on its surface is separated along the division lines together with an adhesive film attached to the back surface of the wafer, comprising: an attachment step of attaching an expanded sheet to the back surface of the wafer via the adhesive film; an expansion step of expanding the expanded sheet after the attachment step; a light irradiation step of irradiating the adhesive film with light of an absorbent wavelength from one side of the wafer after the expansion step; and after the light irradiation step, The light irradiated in the light irradiation step On the other side of the wafer The positioned cameras receive light, The method is characterized by including a separation detection step, which involves detecting whether or not light is leaking from the line to be divided, determining that the wafer and the adhesive film are separated if light is leaking, and determining that an unseparated region exists if no light is leaking.

[0010] In the wafer separation and detection method described above, the wavelength range of the light irradiated in the light irradiation step may be 280 nm or more and 300 nm or less. [Effects of the Invention]

[0011] This invention has the effect of being able to detect unseparated areas in an adhesive film. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic perspective view showing an example of a wafer to be processed in the wafer separation and detection method according to Embodiment 1. [Figure 2] Figure 2 is a flowchart showing the flow of the wafer separation and detection method according to Embodiment 1. [Figure 3] Figure 3 is a schematic side view showing a partial cross-section of a separation and detection apparatus that performs the extended step, light irradiation step, and separation and detection step of the wafer separation and detection method shown in Figure 2. [Figure 4]Figure 4 is a schematic side view showing a partial cross-section of the extended steps of the wafer separation and detection method shown in Figure 2. [Figure 5] Figure 5 is a schematic side view showing a partial cross-section of the light irradiation step of the wafer separation and detection method shown in Figure 2. [Figure 6] Figure 6 is a schematic diagram illustrating an example of an image obtained by the imaging camera during the separation detection step of the wafer separation detection method shown in Figure 2. [Figure 7] Figure 7 shows the measurement results of the light transmittance of the adhesive film. [Modes for carrying out the invention]

[0013] Embodiments for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by those skilled in the art, and those that are substantially the same. In addition, the components described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the present invention.

[0014] [Embodiment 1] A wafer separation and detection method according to Embodiment 1 of the present invention will be described with reference to the drawings. Figure 1 is a schematic perspective view showing an example of a wafer to be processed by the wafer separation and detection method according to Embodiment 1. Figure 2 is a flowchart showing the flow of the wafer separation and detection method according to Embodiment 1.

[0015] (wafer) The wafer separation detection method according to Embodiment 1 is a method for detecting whether the wafer 1 shown in FIG. 1 is separated together with the adhesive film 13. The wafer 1 to be processed in the wafer separation detection method according to Embodiment 1 is a disk-shaped semiconductor wafer or an optical device wafer having a substrate such as silicon, sapphire, gallium arsenide or SiC (silicon carbide). As shown in FIG. 1, a plurality of division planned lines 3 are formed in a lattice pattern on the surface 2 of the wafer 1, and devices 4 are formed in each region partitioned by the division planned lines 3.

[0016] The device 4 is, for example, an integrated circuit such as an IC (Integrated Circuit) or an LSI (Large Scale Integration), an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), or various memories (semiconductor storage devices).

[0017] The wafer 1 is irradiated with a laser beam having a wavelength that is transmissive to the substrate from the back surface 5 side of the surface 2 along the division planned line 3, and a modified layer 6 (shown by a dotted line in FIG. 1) that is a division starting point is formed inside the substrate along the division planned line 3. The wafer 1 is divided into individual chips 10 starting from the modified layer 6. The chip 10 includes a part of the substrate divided along the division planned line 3 and a device 4 formed on the surface of the substrate, and a part of the adhesive film 13 divided on the back surface 5 of the substrate is attached thereto.

[0018] The modified layer 6 means a region in which the density, refractive index, mechanical strength and other physical properties are different from those of the surroundings, and examples thereof include a melting treatment region, a crack region, an insulation breakdown region, a refractive index change region, and a region in which these regions are mixed.

[0019] After a modified layer 6 is formed inside the substrate along the planned division line 3, an adhesive film 13 attached to an expanded sheet 12 with an annular frame 11 attached to its outer edge is attached to the back surface 5, and the wafer 1 is supported by the expanded sheet 12 within an opening inside the frame 11. After the wafer 1 is supported by the expanded sheet 12 within the opening inside the frame 11, the area between the outer edge of the wafer 1 on the expanded sheet 12 and the inner edge of the frame 11 is expanded, and the wafer is divided into individual chips 10 along the planned division line 3 starting from the modified layer 6. Also, when the wafer 1 is divided into individual chips 10, the adhesive film 13 is divided for each chip 10.

[0020] (Wafer separation and detection method) The wafer separation detection method according to Embodiment 1 is a method for detecting whether a wafer 1, which has a plurality of division lines 3 formed in a grid pattern on its surface, is separated along the division lines 3 together with an adhesive film 13 attached to the back surface 5 of the wafer 1. The wafer separation detection method according to Embodiment 1 is also a method in which an expanded sheet 12 is attached to the back surface 5 of the wafer 1 via the adhesive film 13, and then the expanded sheet 12 is expanded to divide the wafer 1 into individual chips 10 along the division lines 3, and the adhesive film 13 is also divided for each individual chip 10. As shown in Figure 2, the wafer separation detection method according to Embodiment 1 comprises an attachment step 101, an expansion step 102, a light irradiation step 103, and a separation detection step 104.

[0021] (Attachment step) The attachment step 101 is the step of attaching the expanded sheet 12 to the back surface 5 of the wafer 1 via an adhesive film 13. In Embodiment 1, as shown in Figure 1, in attachment step 101, the adhesive film 13 attached to the expanded sheet 12, which has an annular frame 11 attached to its outer edge, is attached to the back surface 5 of the wafer 1, which has a modified layer 6 formed inside the substrate along the planned division line 3.

[0022] The adhesive film 13 is a die-attach film for die bonding, used to fix individually divided chips 10 to other chips or substrates. In Embodiment 1, the adhesive film 13 is formed in the shape of a disc with the same diameter as the wafer 1.

[0023] The expanded sheet 12 is made of a stretchable resin. The expanded sheet 12 is formed in the shape of a disc with a diameter larger than the diameter of the wafer 1 and the adhesive film 13, and comprises a base layer made of a stretchable synthetic resin and an adhesive layer made of a stretchable synthetic resin that is laminated on the base layer and attached to the wafer 1. The surface of the adhesive layer is the surface to which the adhesive film 13 is attached, and the back surface 5 of the wafer 1 is attached via the adhesive film 13.

[0024] In Embodiment 1, the expanded sheet 12 has an adhesive film 13 pre-attached to the surface to be attached, and is attached to the back surface 5 of the wafer 1 via the adhesive film 13, thus being a so-called 2-in-1 tape.

[0025] The frame 11 is formed in an annular shape with an inner diameter larger than the diameter of the wafer 1 and the adhesive film 13, and the outer edge of the expanded sheet 12 is attached to it.

[0026] In Embodiment 1, in the attachment step 101, the back surface 5 of the wafer 1 is attached to the adhesive film 13 attached to the expanded sheet 12 to which the frame 11 is attached around the outer edge, thereby mounting the wafer 1 to the frame 11 via the expanded sheet 12.

[0027] (Separation and detection device) Next, the separation and detection apparatus 20 that performs the expansion step 102, the light irradiation step 103, and the separation and detection step 104 will be described. Figure 3 is a schematic side view showing a partial cross-section of the separation and detection apparatus that performs the expansion step, the light irradiation step, and the separation and detection step of the wafer separation and detection method shown in Figure 2.

[0028] The separation detection device 20 shown in Figure 3 expands an expanded sheet 12 attached to the back surface 5 of the wafer 1 via an adhesive film 13, thereby separating the wafer 1 into individual chips 10 along the planned division line 3, and also separates the adhesive film 13 for each individual chip 10. The separation detection device 20 also detects whether the wafer 1, separated along the planned division line 3, is separated along the planned division line 3 together with the adhesive film 13 attached to the back surface 5 of the wafer 1.

[0029] As shown in Figure 3, the separation detection device 20 comprises a frame fixing unit 30, an expansion unit 40, a separation detection unit 50, and a control unit 60. The frame fixing unit 30 fixes the frame 11 on which the wafer 1 is mounted via an expandable sheet 12, and comprises a frame mounting plate 31 and a clamping mechanism 32. The frame mounting plate 31 is formed in an annular shape with a circular opening 33 in its planar shape, and its upper surface is a holding surface 34 that is flat and parallel to the horizontal direction. The inner diameter of the opening 33 of the frame mounting plate 31 is smaller than the inner diameter of the frame 11 and larger than the diameter of the wafer 1 and the adhesive film 13. The frame 11 is placed on the holding surface 34 of the frame mounting plate 31 with the wafer 1 positioned on the opening 33.

[0030] Multiple clamping mechanisms 32 are provided at intervals along the circumferential direction of the frame mounting plate 31. The clamping mechanisms 32 clamp and fix the frame 11, which is placed on the holding surface 34, between themselves and the holding surface 34.

[0031] The expansion unit 40 presses the area between the inner edge of the frame 11 and the outer edge of the wafer 1 of the expanded sheet 12 attached to the wafer 1 mounted on the frame 11 fixed by the frame fixing unit 30, from the substrate layer side, which is the back side of the surface to be attached. The expansion unit 40 includes an expansion drum 41.

[0032] In Embodiment 1, the expansion drum 41 is formed in a cylindrical shape, with an outer diameter smaller than the inner diameter of the frame 11 and opening 33 that are placed on the holding surface 34 of the frame mounting plate 31, and an inner diameter larger than the diameter of the wafer 1 and adhesive film 13 that are attached to the expanded sheet 12. The expansion drum 41 is arranged coaxially with the frame mounting plate 31 within the opening 33 of the frame fixing unit 30.

[0033] The expansion drum 41 is attached to a cylinder (not shown) and moves up and down in the Z-axis direction by the cylinder. That is, the expansion drum 41 is attached to the end of the extendable rod of the cylinder and is provided to move up and down in the Z-axis direction as the cylinder rod extends and retracts.

[0034] In Embodiment 1, the expansion drum 41 moves up and down in the Z-axis direction by a cylinder, between a position where its upper end is on the same plane as the holding surface 34 of the frame mounting plate 31 of the frame fixing unit 30, and a position where its upper end is above the holding surface 34 of the frame mounting plate 31 of the frame fixing unit 30.

[0035] As the cylinder rises, the upper end is positioned above the holding surface 34 of the frame mounting plate 31 of the frame fixing unit 30 that secures the frame 11. Therefore, the expansion drum 41 presses against the area between the inner edge of the frame 11 and the outer edge of the wafer 1 of the expanded sheet 12 to which the wafer 1 attached is mounted on the frame 11 that is fixed by the frame fixing unit 30.

[0036] The separation detection unit 50 detects whether the wafer 1 is separated along the separation line 3 into individual chips 10 together with the adhesive film 13 along the separation line 3. The separation detection unit 50 includes a light source 51 and an imaging camera 52. The light source 51 is positioned on one side of the wafer 1, from the front surface 2 to the back surface 5, which is mounted on a frame 11 fixed by a frame fixing unit 30, and irradiates light 53 (shown in Figure 5) of an absorbent wavelength through the adhesive film 13. In Embodiment 1, the light source 51 is positioned in the center inside the expansion drum 41 and on the back surface 5 side, which is one side of the wafer 1 mounted on the frame 11 fixed by the frame fixing unit 30. In Embodiment 1, the wavelength range of the light 53 irradiated by the light source 51 is 280 nm or more and 300 nm or less.

[0037] The imaging camera 52 is positioned on the other side of the wafer 1's surface 2 and back surface 5, which is mounted on a frame 11 fixed by a frame fixing unit 30, and detects whether or not light 53 is leaking from the division line 3. In Embodiment 1, the imaging camera 52 is positioned above the center of the opening 33 of the frame fixing unit 30 and is located on the other side, the surface 2, of the wafer 1 mounted on the frame 11 fixed by the frame fixing unit 30.

[0038] In Embodiment 1, the imaging camera 52 is equipped with an image sensor capable of receiving at least the light 53 irradiated by the light source 51. The image sensor is, for example, a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary MOS) image sensor. The imaging camera 52 detects whether or not light 53 is leaking from the division line 3 by imaging the surface 2 side of the wafer 1 mounted on the frame 11 fixed by the frame fixing unit 30. The imaging camera 52 captures an image and outputs it to the control unit 60.

[0039] The control unit 60 controls the aforementioned components of the separation detection device 20 to cause the separation detection device 20 to perform processing operations on the wafer 1. The control unit 60 is a computer having an arithmetic processing unit with a microprocessor such as a CPU (central processing unit), a storage device with memory such as ROM (read-only memory) or RAM (random access memory), and an input / output interface device. The arithmetic processing unit of the control unit 60 performs calculations according to the computer program stored in the storage device and outputs control signals for controlling the separation detection device 20 to the aforementioned components of the separation detection device 20 via the input / output interface device.

[0040] The control unit 60 is connected to a display unit (not shown) which consists of a liquid crystal display device that displays the status of machining operations and images, and an input unit (not shown) which is used by the operator to register machining conditions, etc. The input unit consists of at least one of a touch panel provided on the display unit and an external input device such as a keyboard.

[0041] (Extension step) Figure 4 is a schematic side view showing a partial cross-section of the expansion step of the wafer separation and detection method shown in Figure 2. The expansion step 102 is a step in which the expanded sheet 12 is expanded after the attachment step 101.

[0042] In expansion step 102, the separation detection device 20 lowers the expansion drum 41 of the expansion unit 40, stops the irradiation of light 53 from the light source 51, and releases the clamp of the clamp mechanism 32 of the frame fixing unit 30. Then, the frame 11 with the wafer 1 mounted on it is carried onto the holding surface 34 of the frame mounting plate 31 by a transport unit (not shown). In expansion step 102, the separation detection device 20 clamps the frame 11 to the frame mounting plate 31 with the clamp mechanism 32, and the frame fixing unit 30 fixes the frame 11. In Embodiment 1, once the frame 11 is fixed, in expansion step 102, the back surface 5 of the wafer 1 faces the light source 51 via the adhesive film 13 and the expanded sheet 12, and the front surface 2 faces the imaging camera 52. However, in the present invention, the front surface 2 may face the light source 51 and the back surface 5 may face the imaging camera 52.

[0043] In expansion step 102, the separation detection device 20 raises the expansion drum 41 of the expansion unit 40, as shown in Figure 4. The upper end of the expansion drum 41 then contacts the area of ​​the expanded sheet 12, and the upper end presses the area of ​​the expanded sheet 12 from below upward, causing the expanded sheet 12 to expand in the planar direction. As a result of the expansion of the expanded sheet 12 in expansion step 102, tensile forces act radially on the expanded sheet 12.

[0044] When a radial tensile force is applied to the expanded sheet 12 attached to the back surface 5 of wafer 1, the wafer 1 is divided into individual chips 10 along the planned division line 3, using the modified layer 6 as a starting point, because a modified layer 6 has been formed along the planned division line 3. In addition, the wafer 1 expands, creating gaps between the chips 10. Furthermore, when a radial tensile force is applied to the expanded sheet 12, the adhesive film 13 breaks along the modified layer 6, i.e., the planned division line 3, for each individual chip 10, and the chips attached to adjacent chips 10 separate across the planned division line 3. Note that in expansion step 102, the adhesive film 13 may not break along some of the planned division lines 3.

[0045] (Light irradiation step) Figure 5 is a schematic side view showing a partial cross-section of the light irradiation step of the wafer separation and detection method shown in Figure 2. The light irradiation step 103 is a step in which light 53 of a wavelength that has absorption properties is irradiated onto the adhesive film 13 from the back side 5, which is one side of the wafer 1, after the expansion step 102. In Embodiment 1, in the light irradiation step 103, the separation and detection device 20 irradiates light 53 onto the back side 5 of the wafer 1, which is mounted on a frame 11 fixed by a frame fixing unit 30, via the expanded sheet 12, as shown in Figure 5. Thus, in Embodiment 1, the wavelength range of the light 53 irradiated in the light irradiation step 103 is 280 nm to 300 nm.

[0046] (Separation and detection step) Figure 6 is a schematic diagram showing an example of an image obtained by the imaging camera during the separation detection step of the wafer separation detection method shown in Figure 2. The separation detection step 104 is a step in which, after the light irradiation step 103, it is detected whether or not light 53 is leaking from the planned separation line 3 on the other side of wafer 1, which is the surface 2 side. If light 53 is leaking, it is determined that wafer 1 and adhesive film 13 have been separated, and if light 53 is not leaking, it is determined that an unseparated region 7 exists.

[0047] In Embodiment 1, during the separation detection step 104, the separation detection device 20 uses an imaging camera 52 to image the wafer 1, and the control unit 60 acquires an image 54, shown as an example in Figure 6, from the imaging camera 52. In the image 54 shown as an example in Figure 6, the outline of the wafer 1 and the division lines 3 of the wafer 1 that received light 53 are shown as solid lines, while the division lines 3 that did not receive light are shown as dashed lines.

[0048] If the light 53 is at a wavelength that is absorbed by the adhesive film 13, and the adhesive film 13 is not divided along the division line 3, then even if the wafer 1 is divided along the division line 3, the adhesive film 13 will absorb and block the light 53. For this reason, in the regions where the adhesive film 13 is not divided along the division line 3, the light 53 is not received by the imaging camera 52. For this reason, in the image 54 captured by the imaging camera 52, the division line 3 that received light 53 indicates that the adhesive film 13 is divided, while the division line 3 that did not receive light 53 indicates that the adhesive film 13 is not divided.

[0049] In Embodiment 1, in the separation detection step 104, the control unit 60 detects whether the imaging camera 52 has captured an image 54 and received light 53 from each planned division line 3, and detects whether light 53 is leaking from each planned division line 3. In Embodiment 1, in the separation detection step 104, the control unit 60 determines that the wafer 1 and adhesive film 13 have separated and separated the planned division line 3 that the imaging camera 52 has captured an image 54 and received light 53 from, i.e., the planned division line 3 that is leaking light 53. In Embodiment 1, in the separation detection step 104, the control unit 60 determines that the planned division line 3 that the imaging camera 52 has not captured an image 54 and did not receive light 53 from, i.e., the planned division line 3 that is not leaking light 53, is an unseparated region 7 that at least one of the wafer 1 and adhesive film 13 has not separated. Note that the planned division line 3 shown by the dashed line in Figure 6 is the unseparated region 7.

[0050] Thus, in Embodiment 1, in the separation detection step 104, the control unit 60 determines that the wafer 1 and adhesive film 13 are separated if light 53 leaks from the image 54 captured by the imaging camera 52, and determines that there is an unseparated region if light 53 does not leak. In Embodiment 1, in the separation detection step 104, the control unit 60 stores the determination result and terminates the wafer separation detection method.

[0051] As described above, the wafer separation detection method according to Embodiment 1 involves irradiating the wafer 1 with light 53 of a wavelength absorbed by the adhesive film 13 from the back surface 5 side in the light irradiation step 103, and determining in the separation detection step 104 whether light 53 is leaking from the division line 3 on the front surface 2 side. For this reason, the wafer separation detection method according to Embodiment 1 can detect whether or not the adhesive film 13 has been divided and separated along the division line 3.

[0052] As a result, the wafer separation detection method according to Embodiment 1 has the effect of being able to detect the unseparated region 7 of the adhesive film 13.

[0053] Next, the inventors of the present invention measured the light transmittance 53 of the adhesive film 13 to confirm the effects of the present invention. The results are shown in Figure 7. Figure 7 is a diagram showing the measurement results of the light transmittance of the adhesive film.

[0054] In Figure 7, Example 1, shown by the solid line, shows the light transmittance 53 of an adhesive film 13 with a thickness of 10 μm; Example 2, shown by the dashed line in Figure 7, shows the light transmittance 53 of an adhesive film 13 with a thickness of 20 μm; and Example 3, shown by the dashed line in Figure 7, shows the light transmittance 53 of an adhesive film 13 with a thickness of 30 μm. The horizontal axis represents the wavelength of light 53 irradiated onto the adhesive film 13, and the vertical axis represents the transmittance related to the absorption rate of light 53 at each wavelength of the adhesive film 13.

[0055] As shown in Figure 7, the transmittance of the adhesive film 13 to light 53 with a wavelength range of 280 nm or more and 300 nm or less was 0% or more and 10% or less. Therefore, as shown in Figure 7, it became clear that by irradiating the wafer 1 with light 53 with a wavelength range of 280 nm or more and 300 nm or less from one side and determining whether light 53 is leaking from the planned division line 3 on the other side, it is possible to detect whether the adhesive film 13 is being divided and separated along the planned division line 3.

[0056] It should be noted that the present invention is not limited to the embodiments described above. That is, it can be implemented with various modifications without departing from the core of the present invention. In this invention, the wafer 1 may be divided into individual chips 10 along the division line 3 by cutting or laser processing before the bonding step 101. In this case, in the expansion step 102, the wafer 1 is divided into individual chips 10, and the adhesive film 13 is divided for each individual chip 10, separating them from one another. [Explanation of symbols]

[0057] 1 wafer 2. Surface (the other side) Planned division lines (3 divisions) 5. Reverse side (one side) 7 Unseparated area 12 Expandable Sheets 13 Adhesive film 53 light 101 Application Step 102 Extension Step 103 Light irradiation step 104 Separation and Detection Step

Claims

1. A wafer separation detection method for detecting whether a wafer having multiple division lines formed in a grid pattern on its surface is separated along the division lines together with an adhesive film attached to the back surface of the wafer, The process includes a bonding step of attaching an expanded sheet to the back surface of the wafer via the adhesive film, Following the application step, an expansion step is performed to expand the expanded sheet, Following the expansion step, a light irradiation step is performed, in which light of an absorbable wavelength is irradiated onto the adhesive film from one side of the wafer. The separation detection step includes, after the light irradiation step, receiving the light irradiated in the light irradiation step with a camera positioned on the other side of the wafer, detecting whether or not light is leaking from the planned division line, determining that the wafer and the adhesive film are separated if light is leaking, and determining that an unseparated region exists if no light is leaking. A method for separating and detecting wafers, characterized by the features described above.

2. The wafer separation and detection method according to claim 1, wherein the wavelength range of the light irradiated in the light irradiation step is 280 nm or more and 300 nm or less.

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